Complete genome sequence and comparative genome analysis of enteropathogenic Escherichia coli O127:H6 strain E2348/69.
Enteropathogenic Escherichia coli (EPEC) was the first pathovar of E. coli to be implicated in human disease; however, no EPEC strain has been fully sequenced until now. Strain E2348/69 (serotype O127:H6 belonging to E. coli phylogroup B2) has been used worldwide as a prototype strain to study EPEC biology, genetics, and virulence. Studies of E2348/69 led to the discovery of the locus of enterocyte effacement-encoded type III secretion system (T3SS) and its cognate effectors, which play a vital role in attaching and effacing lesion formation on gut epithelial cells. In this study, we determined the complete genomic sequence of E2348/69 and performed genomic comparisons with other important E. coli strains. We identified 424 E2348/69-specific genes, most of which are carried on mobile genetic elements, and a number of genetic traits specifically conserved in phylogroup B2 strains irrespective of their pathotypes, including the absence of the ETT2-related T3SS, which is present in E. coli strains belonging to all other phylogroups. The genome analysis revealed the entire gene repertoire related to E2348/69 virulence. Interestingly, E2348/69 contains only 21 intact T3SS effector genes, all of which are carried on prophages and integrative elements, compared to over 50 effector genes in enterohemorrhagic E. coli O157. As E2348/69 is the most-studied pathogenic E. coli strain, this study provides a genomic context for the vast amount of existing experimental data. The unexpected simplicity of the E2348/69 T3SS provides the first opportunity to fully dissect the entire virulence strategy of attaching and effacing pathogens in the genomic context.
Iguchi
Atsushi
A
Division of Bioenvironmental Science, Frontier Science Research Center, University of Miyazaki, Miyazaki, Japan.
Thomson
Nicholas R
NR
Ogura
Yoshitoshi
Y
Saunders
David
D
Ooka
Tadasuke
T
Henderson
Ian R
IR
Harris
David
D
Asadulghani
M
M
Kurokawa
Ken
K
Dean
Paul
P
Kenny
Brendan
B
Quail
Michael A
MA
Thurston
Scott
S
Dougan
Gordon
G
Hayashi
Tetsuya
T
Parkhill
Julian
J
Frankel
Gad
G
D055028:Comparative Genomic Hybridization / Q000379:methods; D017124:Conserved Sequence; D004269:DNA, Bacterial / Q000235:genetics; D004270:DNA, Circular / Q000235:genetics; D003967:Diarrhea / Q000382:microbiology; D054308:Enteropathogenic Escherichia coli / Q000235:genetics* / Q000472:pathogenicity; D005798:Genes, Bacterial / Q000235:genetics; D016680:Genome, Bacterial; D006801:Humans; D007223:Infant; D010957:Plasmids; D014178:Translocation, Genetic; D014774:Virulence / Q000235:genetics
D004269:DNA, Bacterial; D004270:DNA, Circular